Solar power technology, or photovoltaics, is a technology that uses solar cells or solar arrays to convert light from the sun into solar-generated electricity. The manufacture and use of photovoltaic cells has expanded significantly in recent years in several countries, including the United States, due to economic incentives and advantages such as the absence of pollution during use, low operating costs, and minimal maintenance.
Solar-generated electricity is particularly useful in locations where grid connection or fuel transport is difficult, costly or impossible such as on satellites, islands, remote locations, and ocean vessels. Photovoltaics can provide a supplemental source of electricity during times of peak demand to reduce grid loading and eliminate the need for local battery power.
Virtually all commercial photovoltaic cells are based on silicon. The most efficient cells use crystalline or polycrystalline silicon as the photoactive medium. These cells are expensive to make. Cells that are made using amorphous silicon are cheaper but less efficient. Although silicon solar cells do not create pollution under operation, their manufacture is a serious source of pollution such that some environmentalists no longer consider photovoltaic energy conversion to be a “green” technology. Some photovoltaic cells include cadmium, which is a highly toxic metal that is harmful to animal life and difficult to remove from the environment. Moreover, its disposal also presents problems due to its toxicity.
Others have developed other types of photovoltaic cells using other types of compounds. For example, U.S. Pat. No. 7,109,136 to Senecal discloses electrospun conducting polymer membranes and composites that have high surface areas and are lightweight, tunable and active (electrically, chemically and optically). Senecal's electrospun conducting polymer membranes and composites are used for applications relating to ionic and electrical conductivity, photovoltaic devices, electrostatic dissipation, chemical sensing, corrosion protection, electromagnetic interference shielding and radar attenuation. Senecal further discloses an electrospinning process wherein a small amount of soluble conducting polymer is added to the polymer solutions used for spinning (known in the art as “spin dopes”). The conducting polymers of Senecal (from organic or aqueous solution or as solid dispersions) are added directly into a spin dope mixture and applied to various surfaces, such as metals, semiconductors, glass and textiles, or processed as stand alone membranes, using electro spinning technologies. U.S. Pat. No. 7,135,261 to Yamazaki discloses a multi-layered organic electrophotographic photoconductor that shows stability in mass production and adhesion ability with two layers contacting the charge generation layer. The photoconducter is free of contamination of the coating liquid for a charge transport layer during a dip-coating process due to dissolution of the charge generation layer. The multi-layered organic electrophotographic photoconductor includes a conductive substrate and an undercoat layer containing a thermosetting resin, a charge generation layer containing a charge generation material and an organic binder resin, and a charge transport layer laminated sequentially on the substrate. A disadvantage of the Yamazaki design is that its efficiency is insufficient for practical use in a photovoltaic system.
In light of the drawbacks discussed above, what is needed is a non-toxic photovoltaic technology that converts solar energy effectively and efficiently to electricity without causing pollution during or after manufacture.